Mode of Nutrition in Plants

MODE OF NUTRITION IN PLANTS

BY

ARNAB BASHISTHA

BOTANY MAJOR

1ST SEM

BAJALI COLLEGE’14

WHAT IS NUTRITION:

• It is the process of taking in of food.

• The energy which is stored within the food materials is used by

the living organisms for various activities.

• Nutrition occurs in several stages like ingestion, digestion,

absorption, assimilation and egestion.

MODE OF NUTRITION IN PLANTS:

• Photosynthesis is a type of plant nutrition carried out by green

plants only.All the plants can not get their nourishment

through the process of photosynthesis. Some plants are

dependent on other plants and animal for their food. Different

plants have different nutritional processes.

CLASSIFICATION OF PLANTS ON THE BASIS OF MODE OF NUTRITION:

• Autotrophs:

Epiphytes

• Chemoautotrophs

• Heterotrophs:

Parasites

Saprophytes

Symbiont

Insectivorous Plants

AUTOTROPHS

• The autotrophic plants are all green plants by virtue of the presence of

chlorophyll in their cells.As they can produce their food from inorganic

materials, they are not dependent on other plants or animals for food.

• According to different habitat and environmental conditions autotrophs

have structural differences.They range from unicellular type (algae e.g.

Chlamydomonas) to large branched trees.

• Epiphytes (e.g. some orchids) are a kind of autotrophs which only live on

other plants but do not take any food from that plant.

CHEMOAUTOTROPHS

• They prepare their own food by the process of chemosynthesis

i.e. the process of carbohydrate formation in which chemical

reaction is used to obtain energy from inorganic compounds.

• Example: Sulphur bacteria like Beggiatoa convert H2S to Sulphur

and releases enegy.

2H2S + O2 2H2O + 2S + energy

HETEROTROPHS

• The heterotrophic plants are incapable of

photosynthesizing.They are non-green i.e. they lack of

chlorophyll.They obtain certain organic compounds (food) from

other autotrophs.

• They may be saprophytes, parasites, symbionts or

insectivorous.

Saprophytes:

• They get their nutrition from dead or decaying organic matter.

• They may be obligate saprophytes (i.e. they can live only on

dead organic matter) or facultative saprophytes (i.e. they are

mainly parasitic organism with the ability to survive for a part

of its life cycle as a saprophyte).

• Examples: Neottia , Monotropa etc.

Parasites:

• They get their nutrition from the host.The parasites maintain their physical contacts with the host plant through haustoria(parasitic roots).

• Parasites may be of two types- Obligate parasite (i.e. they are parasitic organism that can’t completes its life cycle without exploiting a suitable host) and Facultative parasite (i.e. they may resort to parasitic activity but absolutely rely on any host for completion of its life cycle).

• They may live on the stem or on the roots of the host.They may be partially autotrophic and partially parasitic.On this basis parasites are –

a. Total stem parasite

b. Partial stem parasite

c. Total root parasite

a. Total stem parasite: They totally depend

on the host plant as they lack of

chlorophyll.Example: Cuscuta

b. Partial stem parasite: They depend on the

host plants only for water and minerals, but

they bear chlorophyll and get nutrition

through the process of

photosynthesis.Example: Viscum

c. Total root parasite: They live on

the roots the host and get their

nourishment.Example: Raflessia,

Orobanchae

d. Partial Root Parasite: They possess

chlorophyll but for germination of

their seeds they follow parasitism

on roots of the host.Example:

Santalum album

Symbionts:

• It means the close association between two different plants of

different categories.In this association both the plants get

benifited.

• Examples: Lichen(association between algae and fungi),

Mycorrhiza(fungal association with the roots of higher plants)

etc.

Insectivorous Plants:

• They have the mechanism to trap insects and are adapted to

digest the protein matter contained in insects.They depend

only partially on nutrition as they bear normal leaves and roots.

• Examples: Nepenthes, Drossera, Dionea, Utricularia etc.

LET’S SEE HOWTHE HERO KILLS THE VILLAIN

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